This invention relates generally to key operated mechanical actuators for electrical switches, and more particularly pertains to a key operated switch actuator used as a "door control switch" on mass transit vehicles such as subway cars.
Door control switches are well known and many are in common use on mass transit vehicles. In this application, a rugged, easy to operate, key operated switch is required to provide access to transit cars by authorized transit authority personnel as required for efficient train operation and maintenance. An earlier crew switch of this type is disclosed and claimed in U.S. Pat. No. 4,153,826, assigned to the same assignee as this application. U.S. Pat. No. 4,153,826 is hereby incorporated by reference.
The switch disclosed in U.S. Pat. No. 4,153,826, although providing satisfactory operation, has, due to changing requirements of the transit industry, substantial shortcomings in that more complex train control systems require a greater number of circuits, resulting in use of the multiple stack rotary electromechanical switch, typically operated by the actuator disclosed herein. Key operation in order to prevent train operation by unauthorized personnel is also required.
Present efforts to utilize electromechanical switches such as the "electroswitch" series 31 operated by a conventional high security lock such as the Chicago Lock Company number 4188, or other use of a high security lock actuator have not been particularly successful. Primary deficiencies encountered in utilizing these conventional locks to operate an electromechanical switch include short switch life due to excessive force transmitted through key operation. Also, conventional high security keys cannot withstand the relatively rugged conditions surrounding transit car use by operating personnel.
It is therefore the object of this invention to provide a highly reliable, simple, mechanically rugged electromechanical switch actuator, operated by a detachable key.
It is a further object of this invention to provide an electromechanical switch actuator having a retained operating key for predetermined switch positions.
It is a further object of this invention to provide an electromechanical switch actuator having a non-electrical switch position indicator independent of key presence.
It is yet an additional object of this invention to provide an electromechanical switch actuator wherein the switch function or position is indicated by key orientation.
It is a further object of this invention to provide an electromechanical switch actuator wherein the mechanical operating key forces are converted entirely into rotational torque.
It is another object of this invention to provide an electromechanical switch actuator wherein an operating key introduced external the car body operates a switch entirely internal of the car body.